Temporal factors and physiological load. Paper presented at the Symposium held in Amsterdam, September 1969, sponsored by the International Ergonomics Association.

The acceptability of any human task must be based on relevant data about the requirements of the task, including the working time and on information about the operator's capacity. The stage of complete ignorance about time factors in operator performance is passed, but there are still good reasons to pay more attention to this aspect of the functioning of man, both in research and in practice.